The skin element includes an inner and an outer surface. The transverse stiffening elements can, for example, be in the form of frames and lie, preferably parallel, spaced apart from each other against the inner surface of the skin element. The longitudinal stiffening elements can, for example, be designed as stringers and lie, preferably parallel, spaced apart from each other and transverse to the transverse stiffening elements against the inner surface of the skin element. The longitudinal stiffening elements can extend approximately parallel to each other, however they can also, as in the case of the tail area of an airplane fuselage for example, run closer towards each other or further apart from each other. The same applies to the transverse stiffening elements, which can also extend approximately parallel to each other or run closer towards each other.
The skin element includes a multitude of skin sections, each of which is defined between two neighboring transverse stiffening elements and two neighboring longitudinal stiffening elements. Thus, between a first and a second transverse stiffening element viewed in the longitudinal direction and also between a first and a second longitudinal stiffening element viewed in the transverse direction, a first skin section is defined.
Such aircraft structural components have long been known about from the prior art and are commonly used in airplane construction, in particular for fuselage construction, where the longitudinal stiffening elements then extend parallel to the longitudinal axis of the airplane, but also for the wings, tail unit or flaps. The longitudinal stiffening elements primarily serve two main purposes. Firstly, they serve to transmit forces in a longitudinal direction of the aircraft structural component, in other words, in the direction of extension of the longitudinal stiffening elements and transverse to the direction of extension of the transverse stiffening elements. Secondly, they serve to support and stabilize the skin element and prevent local occurrence of buckling on the skin element.
At the same time, however, every longitudinal stiffening elements involves its own costs, for example the costs of production and of integration of the longitudinal stiffening element into the aircraft structural component, and plays a part in increasing the weight of the aircraft structural component and thus in increasing the empty weight of the aircraft it is part of, and both of these factors are generally disadvantageous. Accordingly, longitudinal stiffening elements should be used in an aircraft structural component only where they are absolutely essential.
It has been discovered that in numerous aircraft structural components, most of the longitudinal stiffening elements have the minimum diameter, because in their current number, that is to say, with the current spacing between each other, they are needed to prevent local buckling, but are not, however, needed for the transmission of longitudinal forces. In other words, in the case of most of the longitudinal stiffening elements, the criterion which determines the spacing between the longitudinal stiffening elements and thus the quantity of longitudinal stiffening elements, is the prevention of local buckling, and not the transmission of longitudinal forces. Therefore, if it were possible to reduce the influence of the spacing between the longitudinal stiffening elements on the buckling behavior of the skin element, the longitudinal stiffening elements could be employed with significantly greater spacing between each other and therefore in a significantly smaller quantity.
From the patent DE 10 2010 035 787 A1 an airplane structural component is known, the skin element of which is constructed in a sandwich construction with an inner and an outer face sheet and between the face sheets a core layer, which extends along the longitudinal stiffening elements.